In order to improve the absorption, solubility, content uniformity and AUC (bioavailability), among others, of a sparingly soluble drug, it is generally considered desirable to micronize the drug. Actually, for providing sparingly soluble drugs in the tablet or the like pharmaceutical dosage form, they are micronized into fine powders on many occasions.
The pulverizing systems for such micronization can be roughly classified into an open-circuit pulverizing system and a closed-circuit pulverizing system. The open-circuit pulverizing system comprises passing a pulverization load a few times within one minute or substantially only once through a pulverizing zone and the closed-circuit pulverizing system comprises passing a pulverization load many a time during a comparatively long time through a pulverizing zone.
Meanwhile, drugs in general may usually remain in a thermodynamically stable state in a crystalline form than in a non-crystalline form and, therefore, in consideration of the stability of the drug, the pulverizate of the drug is preferably provided in a crystalline form barring special circumstances.